On clock faces, 4 is Expressed as IIII, not IV

Original Article ↗ Hacker News Discussion ↗

Many analog clocks and watches write the number four as “IIII” instead of the more familiar Roman “IV,” a choice rooted in a mix of historical usage, manufacturing convenience, visual balance, and legibility. Commenters note that Roman numerals were never fully standardized in antiquity, that additive forms like IIII and VIIII were common, and that clockmakers may have favored IIII both for symmetry on the dial and to avoid confusion with VI when viewed at odd angles. The thread widens into reflections on how and whether Roman numerals are still taught, how number systems evolve, and the ways modern culture preserves or reinvents older notations.

Historical numeral usage

  • Commenters stress that “IIII” is historically valid Roman notation, not an error.
  • Both additive (IIII, VIIII, XXIIII, etc.) and subtractive (IV, IX, XL) forms coexisted, often mixed even within the same inscription.
  • Evidence cited from coins, classical texts, and monuments suggests subtractive forms existed in Roman times but were not strictly standardized; some say consistent standardization came much later (Middle Ages), but this timing is debated and left unclear.

Aesthetic and design considerations

  • Many argue clockmakers use “IIII” mainly for visual balance and symmetry.
  • Using IIII, V–VIII, and IX–XII yields a pleasing distribution: four numerals with only I, four with V, four with X.
  • Several people note that seeing IV on a dial “looks wrong” simply because IIII has become the conventional aesthetic in horology; it’s widely known as the “watchmaker’s” or “clockmaker’s” four.

Manufacturing and material‑efficiency theories

  • One popular explanation: a single die or plate (e.g., “VIIIIX”) can be stamped four times and cut up to produce all numerals I–XII with minimal waste, which works only if 4 is IIII.
  • Some find this clever and plausible for small workshops; others doubt it yields meaningful savings or matches actual historical manufacturing methods. No consensus emerges.

Legibility and user comprehension

  • Another recurring rationale: with numerals oriented radially, IV near the bottom can be confused with VI when seen upside down or at an angle, especially by semi‑literate viewers reading tower clocks.
  • Critics argue that people know 4 precedes 5 and don’t rely heavily on numerals to read analog time, so this confusion may be overstated.
  • An alternate usability point: IIII is harder to distinguish from III at a glance than IV is, suggesting trade‑offs rather than a clear win.

Religious/taboo and cultural explanations

  • A traditional story holds that IV was avoided because it coincided with an abbreviation of Jupiter’s name, though this is treated more as lore than established fact.
  • Analogies are drawn to Hebrew and Japanese numeral taboos, where certain written forms are altered to avoid sacred or ominous associations.

Roman numerals in modern education and culture

  • Many report minimal or declining instruction in Roman numerals; most exposure now comes from clocks, TV/film copyright dates, the Super Bowl, and Latin classes.
  • Some see value in teaching them briefly to illustrate alternative number systems and “imperfect abstractions”; others view them as low‑priority trivia.
  • Experiences range from teachers insisting IV is the only “correct” 4 to people only later discovering IIII is common and historically grounded.

Related tangents

  • The thread branches into broader discussions of number systems (senary, base‑12, vigesimal French, calendar reforms) and the remarkable longevity and legacy-claims of the Roman Empire, but these are secondary to the clock‑face question.